Single line pneumatic tube system

ABSTRACT

A single line (pressure-vacuum) pneumatic tube system capable of incorporating one or more novel intermediate stations. A unique pressure-vacuum chamber and a novel air shifter valve in the central station provides either pressure or vacuum for the system without turbulence or significant pressure drop. An air relief valve in the tubing significantly reduces noise at the end station. The end station is provided with a valve for return air. The system is unitized eliminating custom design of simple systems.

This is a division of application Ser. No. 38,168 filed May 11, 1979,U.S. Pat. No. 4,251,169, which is a continuation of application Ser. No.876,112 filed Feb. 3, 1978, U.S. Pat. No. 4,189,26, the priority ofwhich is claimed.

BACKGROUND OF THE INVENTION

This invention relates to a unitized single line (pressure-vacuum)pneumatic tube system capable of incorporating intermediate stations,and novel components therefor.

Traditionally, pneumatic tube systems which deliver carriers to one orseveral locations and back have been custom designed, requiringextensive engineering and selection of various components. Single linepneumatic tube systems are well known in the prior art as exemplified byU.S. Pat. Nos. 2,137,750 and 3,232,559 and are utilized for drive-inbanking and tolls as shown in U.S. Pat. Nos. 3,599,898 and No.3,976,264. Such systems normally use a high powered turbine to providethe necessary air; however, the noise level of the turbine is such thatthe turbines are located at a remote location from the terminals.Moreover, the air shifter valve for such a system is usually complicatedand changes the direction of flow causing turbulence. Although somesingle line systems do use smaller blowers, they require a blower ateach terminal location.

Accordingly, a need has existed for a unitized system which can bepackaged and sold by the manufacturer as a complete system eliminatingcustom design. Also, there is a need for a simple single line pneumatictube system having a single power unit which is sufficiently quiet thatit can be installed in a room where people are working. There is also aneed for an air shifter which eliminates changing direction of the air.Further, there is a need for a single line pneumatic tube system whichhas a minimum of noise at the end terminal and which can includeintermediate terminals which can transmit a carrier in either directionwithout complicated valving.

SUMMARY OF THE INVENTION

The single line pneumatic tube system of the present invention iscomprised basically of a central station, including a power unit and acentral terminal; an end terminal; tubing connecting the terminals; andlow voltage wiring. Intermediate terminals capable of transmitting acarrier in either direction may be included. The power unit includes apressure-vacuum chamber formed of a housing having a partition platedividing the housing into two sealed chambers. One or more through flowblowers extend through the plate. The pressure-vacuum chamber has twospaced ports. Mounted on the parts is a novel air shifter valveconnected by a length of flexible tubing to the central terminal. Thevalve has a motor driven angularly reciprocating plate connecting theflexible tubing to either the pressure or vacuum part of thepressure-vacuum chamber. Acoustical insulation in the chamber andhousing reduce noise so that the central station may be located wherepersonnel are working. To eliminate noise at the end terminal, thetubing remotely from the end terminal has a flapper valve which allowsescape of the air permitting a negative drop to the terminal. The endterminal is provided with an automatic valve providing air during vacuumoperation. Each terminal is provided with a guide to facilitate ease ofinitiating carrier transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention--illustrative of the best modein which applicants have contemplated applying the principles--is setforth in the following description and shown in the drawings, and isparticularly and distinctly pointed out and set forth in the appendedclaims.

FIG. 1 is a general diagrammatic view showing the novel single tubepneumatic system of the present invention having one intermediatestation.

FIG. 2 is a front elevational view of the central station and power unitwith the front cover of the power unit removed and the door of thecentral station open.

FIG. 3 is an isometric view of the pressure-vacuum chamber and airshifter valve.

FIG. 4 is a cross sectional view taken along lines 4--4 of FIG. 3.

FIG. 5 is an exploded view of the air shifter valve.

FIG. 6 is an isometric view of the intermediate terminal.

FIG. 7 is a cross sectional side view of the end terminal with the valveopen for vacuum operation.

FIG. 8 is a schematic of master electrical control panel.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As can be seen in FIG. 1, the basic single line pneumatic tube system ofthe present invention is comprised of a central station 10 whichincludes a power unit 12, and a central terminal 14, an end terminal 16,and tubing 18 connecting the terminals. The electronics 19 are locatedin the power unit and low voltage wiring 20 provides electricalconnection between terminals. The tubing remote from the end terminal isprovided with a flapper air relief valve 21 which will automaticallyexhaust air after a carrier has passed the air relief valve andtherefore there is no air exhaust at the end terminal and practically nonoise to disturb personnel in the area. If desired one or moreintermediate terminals 22 may be incorporated into the system. Thesystem is so designed that it may be packaged and sold by a manufactureras a complete system eliminating custom design.

The central station is so designed that it resembles office furniturewith the noise level being sufficiently low that it will not disturbnormal office operations. The central station containing power unit 12is the heart of the system replacing the high noise level turbinetraditionally used to produce the air for the system. Moreover, thepower unit 12 provides both pressure and vacuum for the entire system.The power unit 12 is formed of a rectangular sheet metal housing 24having a removable front panel 26. All six interior sides of the housingare provided with acoustical padding 28, which may be sheets ofpolyester. A pressure-vacuum chamber 30 located in power unit 12provides both pressure and vacuum, see FIG. 3. The chamber 30 is formedof two rimmed truncated cone housings 32-34 which may be vacuum formedABS. Each housing member has diametrically opposed longitudinallyextending grooves 36--36. As seen in FIG. 4, a central partition plate38 is located in grooves 36--36. Partition 38 has at least one motoraperture 40 in which is mounted a flow through blower 42. The partition38 is sealed in the grooves and the motor is sealed in the aperture sothat when the chamber is assembled there is a pressure side and vacuumside. It has been found that Lamb Vacuum Motor, Model 115750 having a 2"orifice operates very satisfactorily producing a volume of approximately110 cfm and a vacuum of 3.4 (inches H₂ O). The number of motors mountedin the partition 38 will depend upon the size of the system. It has beenfound that one motor is sufficient for a 21/2" or a 3" system, twomotors for a 4" or 41/2" system and three motors for a 4"×7" systemdelivering carriers at a speed of approximately twenty five feet persecond. Accordingly, partition 38 will have the requisite number ofapertures for the system. Front housing member 32 is provided with apressure port 44 and a vacuum port 46 which are in communication withthe pressure and vacuum side of the chamber respectively. The rims 48 ofthe housing members are provided with apertures and secured together byfasteners 50. To cut down on noise, the inside of the chamber isprovided with a layer of acoustical padding 52 which may be sheetpolyester. Thus pressure-vacuum chamber provides both air pressure tomove a carrier from the central terminal to a remote terminal and vacuumto return the carrier from a remote terminal to the central terminal.

To shift operation from pressure to vacuum an air shifter valve 52 shownin exploded relation in FIG. 5 is connected to pressure and vacuum ports44-46. The air shifter valve is formed of a base plate 54 which hasports 56-58 which are sealingly attached to pressure and vacuum ports44-46. The base plate may be secured to the pressure vacuum chamber bybrackets 60 which are attached to the rim of the pressure-vacuumchamber. Positioned on top of the base plate 54, is a pivotable member62 which is pivoted at one end about a stud 64 extending up from thebase plate 54. The other end of pivotable member 62 is provided with aport 65 for registry with one of the ports 56-58 in the base plate. Anupstanding portion 66 surrounds the port 65. A flexible tubing 68 isattached to the portion 66 and extends up to and attaches with the inletof central terminal 14. To move pivotable member 62 from registry withpressure port 56 to registry with vacuum port 58 and visa versa, thereis a pivotable fork member 70 which has a pivot slot 72 concentric withthe stud 64 and bifurcated arms 74--74 which surround the upstandingportion 66. A bridge member 76 having an aperture 78 over lying pivotstud 64 is attached to base plate 54. Attached to bridge member 76,there is a drive motor 80 having a drive shaft 82 which extends throughaperture 78 and pivot slot 72 and is attached to fork 70 by connectingmeans 84. It has been found that Model MO 581315A by American Bosch ArmsCorporation will provide the proper actuation, 60° reciprocation. Toassure proper registry, the base plate 54 is provided with stops 86--86.To prevent strain on drive motor 80 during start up and stopping, parts56-58 may be placed so that the included angle from the pivot point tothe centers of the ports 56-58 is 57° with the arms 74--74 of fork 70slightly wider than the upstanding portion 66. Therefore, there will besome play at each end of travel. To maintain the pivotable plate incontact with the base plate 54 a spring member 85 is positioned betweenthe end of the shaft 82 and the pivotable member 62.

As set forth above, the central terminal 14 is located on top of thepower unit 12 and is provided with pressure or vacuum from thepressure-vacuum chamber 30 by the air shifter valve 52 through flexibletubing 68. The central terminal 14 is provided with a door 88 forinserting or removing a carrier 90. The terminal 14 is also providedwith a guide 92 terminating at its top end in a full round section oftubing 94. To start operation, the carrier is inserted into guide 92with the felt of the carrier in contact with tubing section 94. The door88 is then closed which seals the system.

Electrical power for the entire system is provided by attaching anelectrical cable provided with a male plug to a 120 volt alternatingcurrent outlet thereby eliminating the necessity of special electricalwiring. The motors 42 run on 120 vac. All other components including themotor for the air shifter valve operate on 24 volt direct current. FIG.8 is a schematic of the electronics 19 which are of the plug in typelocated on a panel in the power unit, see FIG. 1. Each terminal isprovided with a push button switch which is illustrated when on. Theswitch for pressure operation is labeled 96 and the one for vacuumoperation 97. Engagement of any switch commences operation of thesystem. As can be seen in FIG. 8, engagement of push button 96illuminates the lights to show the system is in operation. It alsoallows current to flow to relay RA energizing it and closing normallyopen contacts RA. This allows current to flow to relay RC energizing itand thereby closing normally open contacts RC and opening normallyclosed contacts RC. Current also flows to timer TR and relay RD whichcloses normally open contacts RD permitting current to flow to relay REenergizing it and contacts RE which commences operation of blowers 42.At the same time, drive motor 80 of air shifter valve 52 is energized,moving pivotable member 62 to a position where port 65 is in registrywith pressure port 44 and air from the pressure side of pressure-vacuumchamber 30 is provided through flexible tubing 68 to the inlet ofcentral terminal 14 causing the carrier to travel through tubing 18 tothe next terminal. The system is powered so that the carrier will travelat approximately twenty five feet per second. The timer TR may beadjusted from 8 seconds to 180 seconds. After the set period, the timerrelay will open the contacts TR cutting off the flow of low voltagepower and shutting off the system. If switch 97 is energized, similaroperations will take place except that air shifter valve 52 will movethe pivotable member 62 to the position where port 65 will be inregistry with the vacuum port 46.

As previously mentioned, there is an air relief valve 21 located in thevertical run of tubing remotely spaced from end terminal 16. After thecarrier passes this point, air will flow through the relief valve andthe carrier will free fall to the end terminal. Therefore, escape of airpressure occurs away from the end terminal and operation is quiet. Ascan be seen in FIG. 7, the end terminal 16 is provided with a guide 98similar to guide 92 of the central terminal. Guide 98 has a section oftubing 100 for insertion of the carrier into the system. Also, thebottom of the end terminal is provided with shock absorbing padding. Endterminal 16 also is provided with a flap valve 102 which is closedduring pressure operation but which automatically opens during vacuumoperation to provide air behind the carrier.

In addition to central terminal 14 and end terminal 16, the system mayinclude one or more intermediate terminals 22. As can be seen in FIG. 6,the intermediate terminal is provided with a roof having two spacedports receiving two spaced facing guides 104--104 each of which has anopening portion facing the other. The guides similar to the guides ofthe other terminals have a portion of full tubing 106 for insertion ofthe carrier into the system. The intermediate terminal has a cushion 108of shock absorbing material to absorb the shock of the carrier. Theguides 104--104 are spaced a sufficient distance from the bottom of theterminal so that air may pass around the carrier after the carrier is inthe terminal. The intermediate terminal is so designed that it willreceive and transmit carriers from either direction. Accordingly,intermediate terminal 22 is provided with switch 96 to provide pressureoperation to forward a carrier to end terminal 16 or anotherintermediate terminal. Terminal 22 is also provided with switch 97 tocommence vacuum operation to return a carrier to the central terminal oran intermediate terminal located between the central terminal andintermediate terminal. Intermediate terminal 22 has a door 110 forremoving or inserting a carrier. As can be seen in FIG. 6, the door 110has a latch 112 which makes three point contact with the inside of thefront panel to assure full closure. Door 88 of central terminal 14 isprovided with similar latch. The latches provide positive closure for anair tight system.

As can be seen from the foregoing, the pneumatic tube system of thepresent invention is so designed that it may be packaged as a unit andeasily installed. The central station includes the power unit andcentral terminal and the only electrical connection is attachment to anormal 120 volt alternating current outlet. Both pressure and vacuum isprovided by the novel pressure-vacuum chamber that is powered by smallflow through blowers. The system is shifted from pressure to vacuum bythe novel air shifter valve which does not require changing of directionand subsequent turbulence. Intermediate terminals may be incorporatedinto the system and carriers may be received and transmitted in eitherdirection from the intermediate terminal. To provide quite operation atthe end terminal, an air relief valve is located in the tubing remotelyspaced from the end terminal. To provide air in back of the carrierduring vacuum operation, the end terminal has a flapper valve whichautomatically opens during vacuum operation.

What is claimed is:
 1. A single line, pressure-vacuum pneumatic tube system comprising:a central station having a terminal to dispatch or receive a carrier, pressure-vacuum power means providing pressure and vacuum, means selectively connecting the power means to the terminal to provide pressure or vacuum to the terminal, means energizing the power means and the selectively connecting means; an end station having a terminal to receive or dispatch a carrier; at least one intermediate station having a terminal to receive or dispatch a carrier; a single line of tubing connecting the terminal of the central station with the terminal of the intermediate station; a single line of tubing connecting the terminal of the intermediate station to the terminal of the end station; the intermediate station provided with means to energize the power means and selectively connecting means to provide vacuum to the system whereby a carrier may be dispatched toward the central station and means to energize the power means and selectively connecting means to provide pressure to the system whereby a carrier may be dispatched toward the end station; and the end station provided with means to energize the power means and selectively connecting means to provide vacuum to the system whereby a carrier may be dispatched toward the intermediate terminal; the intermediate terminal comprising a housing having a roof provided with two spaced ports, each port having a guide portion extending downward into the housing and terminating above the bottom of the intermediate terminal, so that air will flow around the carrier positioned in the housing, the upper end of the guide portion having a cylindrical portion extending downward into the intermediate terminal to facilitate insertion of the carrier for transmission, the intermediate terminal receiving and transmitting carriers in either direction.
 2. The pneumatic tube system specified in claim 1 wherein the pressure-vacuum power means is formed of a housing having a central plate dividing the housing into two sealed chambers, at least one flow through blower sealingly mounted in the plate, a port for each of the chambers.
 3. The system specified in claim 1 wherein there is a cushion at the bottom of the intermediate terminal to absorb shock.
 4. The system of claim 1 further comprising indicator means connected to the intermediate station for indicating when the power means and selectively connecting means are energized.
 5. The system of claim 1 further comprising timer means for automatically de-energizing the power means and selectively connecting means after a preselected period of time.
 6. A single line, pressure-vacuum pneumatic tube system comprising:a central station having a terminal to dispatch or receiver a carrier, pressure-vacuum power means providing pressure and vacuum, means selectively connecting the power means to the terminal to provide pressure or vacuum to the terminal, means energizing the power means and the selectively connecting means; an end station having a terminal to receive or dispatch a carrier; at least one intermediate station having a terminal to receive or dispatch a carrier; a single line of tubing connecting the terminal of the central station with the terminal of the intermediate station; a single line of tubing connecting the terminal of the intermediate station to the terminal of the end station; the intermediate station provided with means to energize the power means and selectively connecting means to provide vacuum to the system whereby a carrier may be dispatched toward the central station and means to energize the power means and selectively connecting means to provide pressure to the system whereby a carrier may be dispatched toward the end station; and the end station provided with means to energize the power means and selectively connecting means to provide vacuum to the system whereby a carrier may be dispatched toward the intermediate terminal, the intermediate terminal comprising a housing having two ports, two sections of tubing, one extending into each port forming a guide member, each member having an inward opening semi-cylindrical portion extending into the interior of the housing and terminating above the bottom of the terminal, the semi-cylindrical portions being similar and spaced and facing each other so that air from either tubing will flow around a carrier to start its transmission, each guide member having within the terminal a full section of tubing to facilitate insertion of a carrier into the tubing for transmission, the terminal receiving and transmitting carriers in either direction through either port.
 7. The system of claim 1 or 6 wherein:the intermediate station is provided with first switch means to energize the power means and selectively connecting means to provide vacuum to the system whereby a carrier may be dispatched toward the central station and second switch means to energize the power means and selectively connecting means to provide pressure to the system whereby a carrier may be dispatched toward the end station, said first and second switch means being connected to a control circuit comprising, first relay means connected to the power means and a source of power for interrupting power to the power means when in a normal open state and communicating power to the power means when in a closed state, second relay means connected to the selectively connecting means and a source of power for providing power to the selectively connecting means to provide vacuum to the system in a first state and providing power to the selectively connecting means to provide pressure to the system in a second state, third relay means connected to the first switch means and the second relay means for placing the second relay means in the first state upon actuation of the first switch, fourth relay means connected to the second switch means and the second relay means for placing the second relay means in the second state upon actuation of the second switch,and fifth relay means connected to the first relay means and the first and second switch means for closing the first relay means when either the first or second switch means is actuated. 